| 摘要 |
PURPOSE:To prevent the malfunctions caused at the time of make and break of a power source in a simple and inexpensive way, by providing a detecting circuit for power source voltage to an stable circuit of a power source for controller and connecting said detecting circuit to a drive power source via an electronic switch. CONSTITUTION:A power source is turned on and the voltage induced to a power source transformer 1 delivers the drive power source +24V through a regulator 4 via a diode bridge 2, etc. While the voltage rectified by a diode bridge 7 delivers the power source voltage +5V for controller through a regulator 15 via a diode 14, etc. Here the output of the regulator 4 is supplied to a transistor Tr12 of a voltage detecting circuit R and never applied to a diode 13. The Tr12 is turned off when the power source is turned off and the output of the regulator 4 turns on a Tr5 of an electronic switch S. Thus the voltage +5V is supplied to the regulator 15 via the diode 13 and the output of this +5V is delivered continuously until the level +24V is reduced down to <=7V or so. This prevents the malfunctions that are caused at the time of make and break of the power source.
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